Compaction behavior of uniaxially cold-pressed Bi–Ta composites

Martin, L.; Hodge, Andrea M.; Campbell, Geoffrey H.

doi:10.1016/j.scriptamat.2007.04.004

Cited by 18 publications

(9 citation statements)

References 19 publications

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“…There, r o is reported to be~15.1 MPa for f W = 0, and increases with increasing f W . A similar effect was reported for Ta-reinforced Bi, [17] where the compaction was performed over the range 140 to 550 MPa in the single-step process used to produce the data for the filled symbols in Figure 2. There does not appear to be any significant published work evaluating the correlation between the yield strength determined from mechanical testing and the yield parameters determined from Eq.…”

Section: A Compaction Behaviorsupporting

confidence: 69%

“…This behavior is consistent with published reports of the compaction of composite mixtures of Bi and Ta powders, Pb and steel spheres, Pb and alumina powders, and plasticene spheres and glass beads. [9,11,17] In contrast, materials such as graphite-reinforced Fe; SiC-, Open symbols represent data from the incremental press-and-measure-technique described in the text. Filled symbols represent data from samples pressed directly to the indicated compaction pressures and characterized ex situ after pressing.…”

Section: A Compaction Behaviormentioning

confidence: 99%

“…Dotted lines represent the upper (HS-U) and lower (HS-L) Hashin-Shtrikman bounds calculated from Eqs. [17] through [21]. Also shown are the experimentally determined C 33 measured in situ (X) and ex situ (s).…”

Section: ½12mentioning

confidence: 99%

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Compaction Behavior and Mechanical Properties of Uniaxially Pressed Bi-W Composites

Martin

Hodge

Campbell

2009

Metall Mater Trans A

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Powder metallurgy is a useful route to forming particulate composite materials; however, the densification of hard and soft powder mixtures is usually inhibited by the more refractory phase. The Bi-W powder compacts were uniaxially pressed at room temperature and the compaction behavior and mechanical properties were evaluated. Pressing was performed in incremental steps from~1 to 540 MPa. After each step, the pressure was relieved and the thickness and sound-wave transit time were measured in situ (in the die), in order to determine the density and sound-wave velocity in the compact. The data show that the unreinforced Bi powder compacts to~98 pct density at 540 MPa. The W reinforcement inhibits the densification process, resulting in increased levels of residual porosity. The compaction behavior was evaluated using a modified Heckel equation, while the porosity dependence of the ultrasonically determined elastic modulus was described by a site percolation approach. Postcompaction sound-wave velocity and Vicker's hardness measurements show <5 pct anisotropy between the axial (pressing) and radial directions. The mechanical characterization illustrates the competing effects of the W reinforcement and the associated residual porosity.

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Section: A Compaction Behaviorsupporting

confidence: 69%

Section: A Compaction Behaviormentioning

confidence: 99%

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Compaction Behavior and Mechanical Properties of Uniaxially Pressed Bi-W Composites

Martin

Hodge

Campbell

2009

Metall Mater Trans A

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“…The Al-Al 2 O 3 composite was formed from Al and Al 2 O 3 powders using ECAP at 200 ∘ C. The low density of these composites was due to the difficulty in the deformation of hard reinforcement particles in the matrix during consolidation [8,9]. It was reported that the yield strength of the composite powder increased with increasing volume fraction of reinforcements [9,36]. The increase of yield strength led to a restriction in the Al [27] Al-Mg [24] Al-Al 3 Mg 2 [38] Fe-TiC [5] AlFe-TiC [25] Cu-Ta [18] BM+SPS BM+CP+S BM+ExC BM+HHP BM+HExt Figure 4: Density of different composites and alloys fabricated by different techniques and consolidation methods.…”

Section: Consolidation Of In Situ Cu-nbc Composite Powdermentioning

confidence: 99%

Comparison of Two Powder Processing Techniques on the Properties of Cu-NbC Composites

Long

Othman

Hussain

et al. 2014

Advances in Materials Science and Engineering

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Anin situCu-NbC composite was successfully synthesized from Cu, Nb, and C powders using ball milling and high pressure torsion (HPT) techniques. The novelty of the new approach, HPT, is the combination of high compaction pressure and large shear strain to simultaneously refine, synthesize, and consolidate composite powders at room temperature. The HPTed Cu-NbC composite was formed within a short duration of 20 min without Fe contamination from the HPT’s die. High porosity of 3–9%, Fe and niobium oxidations, from grinding media and ethanol during ball milling led to low electrical conductivity of the milled Cu-NbC composite. The electrical conductivity of the HPTed Cu-NbC composite showed a value 50% higher than that of milled Cu-NbC composite of the same composition.

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“…2, the temperature of the initially porous Ta during the long expansion phase, ~700 K (compared to ~400 K for the initially full-density shell), is still much lower than the Ta melt temperature, ~4340 K. We do not know if this enhanced heating is enough to change the ductility of the material by a measurable amount. Accordingly, to get closer to or above melt for our first experimental test of this concept of dynamic ductility enhancement we chose to use Bi (actually, a Bi-Ta composite [10]) since it has a much lower melt temperature. As seen in Fig.…”

Section: Simulation Of the Experiments And Comparison To Datamentioning

confidence: 99%

Modeling Dynamic Ductility: An Equation of State for Porous Metals

Colvin¹

2008

AIP Conference Proceedings

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Abstract. Enhanced heating from shock compression of a porous material can potentially suppress or delay cracking of the material on subsequent expansion. In this paper we quantify the expected enhanced heating in an experiment in which a sector of a thin cylindrical shell is driven from the inside surface by SEMTEX high explosive (~1 µs FWHM pressure pulse with peak pressure ~21.5 GPa). We first derive an analytical equation of state (EOS) for porous metals, then discuss the coupling of this EOS with material elastic-plastic response in a 2D hydrocode, and then discuss the modeling of the HE experiment with both fully dense and 10% porous Ta and a Bi/Ta composite. Finally, we compare our modeling with some recent experimental data.

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Compaction behavior of uniaxially cold-pressed Bi–Ta composites

Cited by 18 publications

References 19 publications

Compaction Behavior and Mechanical Properties of Uniaxially Pressed Bi-W Composites

Compaction Behavior and Mechanical Properties of Uniaxially Pressed Bi-W Composites

Comparison of Two Powder Processing Techniques on the Properties of Cu-NbC Composites

Modeling Dynamic Ductility: An Equation of State for Porous Metals

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